Marine propeller



E. SIEVART.

MARINE PROPELLER.

APPLICATION FILED MAR. 3, I919.

1,349,981 Pat nted Aug. 17, 1920.

WITNESSES: I INVENTOR aah/eiv'a/7 ATTORNEY UNITED STATES EDWARD SIEVABT, OF MANITOWOC, WISCONSIN.

MARINE PROPELLER.

Specification of Letters Patent.

Application. filed March 3, 1919. Serial No. 280,472.

To all whom it may concern .citizen of the United States, and resident of Manitowoc in the county of Manitowoc and State of Wisconsin, have invented certain new and useful Improvements in Marine Propellers; and I do hereby declare that the following is a full, clear, and exact description thereof.

My invention relates to new and useful 1mprovements in marine propellers, more particularly of that type includlng a hub portion having radial blades curved transversely to procure propelling impact wlth the water. It is in general the object of my invention to increase the propelling efliciency of devlces of this character and it is more particularly my object to procure such arrangement and relation of the propellin blades that a portion of the water engage by one blade in ts driving rotation is imparted momentum in a direction transverse to the rotatlve axls of the device for propulsion into the body of water immediately rearwardly of the hub of the propeller, thus increasing the back-stop action of the water rearwardly of the propeller and consequently increasin the efficiency of the propeller, thus utlllzlng the entire surfaces of the blades for procuring the propelling action.

It is further my object to procure this ncreased propelling action in a manner 1nvolving a minimum addition of structure in the device, thus conducing to a desired simplicity of structure, with consequent advantages.

With the above and other objects and advantages in view, which will be apparent as the description proceeds, my invention resides in the novel features of construction, combination and arrangement of parts as hereinafter'more particularly described and defined by-the appended claims.

In the accompanying drawings: Figure 1 is an elevational view of a propeller constructed in accordance with my invention, and looking toward the rearward side of the propeller with respect to its direction of propelling movement. I Fig. 2 is an edge view of the propeller. Fig. 3 is a transverse sectional view through the hub portion of the propeller on a plane indicated by the line 3-3 of Fig. 1.

Referring now more particularly to the accompanylng drawings, 5 designates the hub portion of my improved propeller which is provided with the usual ke ed passageway whereby it may be mounte upon 'a drive shaft, and said hub portion is provided preferably adjacent one end with an annular blade wall 6 disposed in a. plane at right angles to the axis of the hub. From the periphery of this wall 6 there projects a plurality of, in the present instance two, blades 7, the inner portions of the blades merging with and forming continuations of the surface of the blade walls. Each blade is twisted to lie at oppositev angles oblique wlth respect to the plane of the blade wall 6, said bladesbeing curved transversely to procure a maximum impact action on the water, the curvature of the blades being increased at their rearward sides with respect to the direction of rotation of said blades. These rearward sides of the blades, designated at a, and which extend toward the eye in the side view shown in Fig. l, have inner surface portions 6 which are curved forwardly with respect to the direction of travel of the ropeller to merge into the wall portion 6, the forward sides of the blade, wlth respect to their direction of rotation, being cut away at their inner portions as shown at 0 whereby to avoid the occurrence of surfaces which would be similar to the surfaces 6 but inclined in opposite directions.

Thus, in the operation of my improved propeller, the outer portions of the blades serve to effect impact engagement with the water in the usual manner directing said water rearwardly to procure the major propelling action- At the inner portions of the blades however, particularly by reason of the undercut or forwardly inclined portions Z) an impact action is procured which tends to discharge the water transversely of the axis of the propeller, immediately behind the blade wall 6 whereby such water will be forced into the body of water immediately rearwardly of the hub of the propeller.

What is claimed is:

1. A propeller comprising a hub portion, an, annular wall portion extending from the hub portion and disposed in a plane at right angles to the axis of the hub portion and a plurality of blades extending radially from said annular wall portion and having their major portions curved transversely whereby they are disposed obliquely with respect to the plane of the annular wall portion, said blades having obliquely undercut rear surfaces on their inner portions Patented Aug. 17, 1920.

merging with the blade wall portion whereby. to direct Water transversely of the hub portion.

2. A )ropeller comprising a hub portion, an annu a1- wall portion extendlng from the hub portion and disposed in a plane at right angles to the axis of the hub portion an a plurality of blades extending radlally from said annular wall portion and having-their major portions, curved transversely whereby they are disposed obliquely with respect to the plane of the annular wall portion, said blades having obliquely undercut rear surfaces on their inner portions merging with the annular wall portion whereby to direct Water transversely of the hub portion, and

the forward inner edge portions of the blades being cut away adjacent the annular wall portion.

In testimony that I claim the foregoing I have hereuntoset my hand at Manitowoc in the county of Manitowoc and State of Wisconsin.

EDWARD SIEVART. 

